Dolphin formed as a tropical depression early on December 8, 2008 to the northwest of Kwajalein Atoll in the Marshall Islands.

On December 17, as Dolphin was approaching the edge of PAGASA's Area of responsibility, it was downgraded to a tropical storm by both the JMA and the JTWC.

[1][2] The storm reached storm-force and attained its extratropical peak intensity with 10-minute maximum sustained winds of 60 knots (110 km/h, 70 mph) on December 4, when it was located far east of Japan; however, the low became developed late on the same day.

At 0600 UTC that morning, the Joint Typhoon Warning Center (JTWC), released a significant tropical weather advisory and rated the chances of the disturbance becoming a significant tropical cyclone within 24 hours as poor, due to a quikscat pass had shown that the low level circulation center had broken down into a wave.

However, after the advisory was released the low level circulation center started to rapidly consolidate, and thus the JTWC initiated issuing warnings at 1200 UTC, December 10, and designated it as Tropical Depression 27W, while it was about 640 km (400 mi) to the east of Guam and moving towards the west.

Early the next day the depression's centre passed about 100 km (62 mi) to the south of Guam and made its closest approach.

[29] Guam government officials reported that there was not much significant damage, with power outages around the island being sporadic which were primarily caused by falling trees and debris.

[29] The M/Bca Mae Jan was a cargo passenger ship which sank on December 14 due to rough seas caused by Typhoon Dolphin.

[30] The Philippine National Disaster Coordinating Council reported on December 17 that the local Government unit of Ballesteros, Cagayan had provided assistance worth 16,500 PHP ($352 2008 USD).

[32] Whilst the Department of Health-Center for Health Development had provided 27,203 PHP ($582 2008 USD) worth of assistance, in the form of drugs, fluids and medicines for the injured victims that were confined at the Ballesteros District Hospital.